The present invention relates to a method and apparatus for quantitative determination of trihalomethanes. More particularly, the present invention relates to a method and apparatus that enables continuous quantitative determination of trihalomethanes without any adverse effects of interfering components.
It has recently been established that trihalomethanes are present in tap water, both in raw and finished states, and this has become a great concern to society because of the potential carcinogenity and mutagenicity of trihalomethanes.
To deal with this problem, the FDA of the United States of America conducted a nationwide survey of total trihalomethane contents in tap water and adopted a regulation requiring that a maximum tolerable level of total trihalomethane contents in tap water should be 100 ppb.
In Japan, too, the Ministry of Public Welfare notified an interim guideline on trihalomethanes in March 1981, which required that the target value of total trihalomethane contents to be controlled should not exceed 100 ppb. Under the circumstances described above, there has been a growing need for the correct measurement of trihalomethanes.
Trihalomethanes can be measured by gas chromatography and the following three methods have been adopted to date: (1) purge-trap; (2) solvent extraction; and (3) headspace.
However, these conventional methods have various problems, such as the need to perform preliminary treatments that are complicated and time-consuming, and inability to conduct continuous measurements.
A technique has recently been proposed that fluorimetric determination of chloroform in water be conducted by utilizing the Fujiwara reaction which involves reaction between alkaline nicotinamide and chloroform to produce a fluorescent condensation compound (Okumura K. et al., Analyst, 107, pp. 1498-1502, 1982). However, this method is not suitable for practical applications since if it is directly applied to tap water in either the raw or finished state, many problems will occur, such as (1) inability to provide correct results on account of the presence of interfering substances and (2) inability to conduct continuous measurements.